ºÝºÝߣ

ºÝºÝߣShare a Scribd company logo

Newton’s 3rd law (2)

•Download as PPTX, PDF•
•
S
Saurabh Patil

This document discusses Newton's third law of motion. It defines Newton's third law as forces always acting in equal but opposite pairs called action-reaction force pairs. Examples are provided such as a person jumping and pushing down on the ground, which then pushes up on the person in reaction. Another example is a rocket launching, where the exhaust gas pushes down on the engine in the action force, and the engine pushes up on the gas in the reaction force, providing thrust. The document also explains weightlessness in terms of free fall, where an astronaut in a falling elevator would feel weightless to a scale according to Newton's third law.

1 of 17
Download to read offline
Newton’s 3rd law (2)
Motivator:- Dr. Bhagwan Sawant Guided By:- Mrs. Anjali Sonawane Student’s Name:- Saurabh Sunil Patil Standard:- 9th Division:- C Roll No:- 9123 Subject:- Science
Newton’s 3rd law (2)
Newton’s 3rd law (2)
• Newton’s third law : • To each and every action, there is equal and opposite reaction • Explanation 3 Newton’s Third Law • According to Newton’s third law of motion, forces always act in equal but opposite pairs. Definition:-
• You constantly use action- reaction force pairs as you move about. 3 Newton’s Third Law • When you jump, you push down on the ground. • The ground then pushes up on you. It is this upward force that pushes you into the air. Action and Reaction Forces Don’t Cancel
Large and Small Objects • When you walk forward, you push backward on the ground. 3 Newton’s Third Law • Your shoe pushes Earth backward, and Earth pushes your shoe forward.
A Rocket Launch • When the rocket fuel is ignited, a hot gas is produced. 3 Newton’s Third Law • As the gas molecules collide with the inside engine walls, the walls exert a force that pushes them out of the bottom of the engine.
• This downward push is the action force. 3 Newton’s Third Law • The reaction force is the upward push on the rocket engine by the gas molecules. • This is the thrust that propels the rocket upward.
Weightlessness • You might have seen pictures of astronauts floating inside a space shuttle as it orbits Earth. 3 Newton’s Third Law • The astronauts are said to be weightless. • Yet the force of gravity on the shuttle is almost 90 percent as large as at Earth’s surface. • Newton’s laws of motion can explain why the astronauts float as if there were no forces acting on them.
Measuring Weight • When you stand on a scale, your weight pushes down on the scale. 3 Newton’s Third Law • This causes the scale pointer to point to your weight.
• At the same time, by Newton’s third law the scale pushes up on you with a force equal to your weight. 3 Newton’s Third Law • This fore balances the downward pull of gravity on you.
Free Fall and Weightlessness • Now suppose you were standing on a scale in an elevator that is falling. 3 Newton’s Third Law • A falling object is in free fall when the only force acting on the force is gravity. • You and the scale are both in free fall.
• Because the only force acting on you is gravity, the scale no longer is pushing up on you. 3 Newton’s Third Law • According to Newton’s third law, you no longer push down on the scale.
• So the scale pointer stays at zero and you seem to be weightless. 3 Newton’s Third Law • Weightlessness is the condition that occurs in free fall when the weight of an object seems to be zero.
Newton’s 3rd law (2)
Newton’s 3rd law (2)

More Related Content

Newton’s 3rd law (2)

  • 2. Motivator:- Dr. Bhagwan Sawant Guided By:- Mrs. Anjali Sonawane Student’s Name:- Saurabh Sunil Patil Standard:- 9th Division:- C Roll No:- 9123 Subject:- Science
  • 5. • Newton’s third law : • To each and every action, there is equal and opposite reaction • Explanation 3 Newton’s Third Law • According to Newton’s third law of motion, forces always act in equal but opposite pairs. Definition:-
  • 6. • You constantly use action- reaction force pairs as you move about. 3 Newton’s Third Law • When you jump, you push down on the ground. • The ground then pushes up on you. It is this upward force that pushes you into the air. Action and Reaction Forces Don’t Cancel
  • 7. Large and Small Objects • When you walk forward, you push backward on the ground. 3 Newton’s Third Law • Your shoe pushes Earth backward, and Earth pushes your shoe forward.
  • 8. A Rocket Launch • When the rocket fuel is ignited, a hot gas is produced. 3 Newton’s Third Law • As the gas molecules collide with the inside engine walls, the walls exert a force that pushes them out of the bottom of the engine.
  • 9. • This downward push is the action force. 3 Newton’s Third Law • The reaction force is the upward push on the rocket engine by the gas molecules. • This is the thrust that propels the rocket upward.
  • 10. Weightlessness • You might have seen pictures of astronauts floating inside a space shuttle as it orbits Earth. 3 Newton’s Third Law • The astronauts are said to be weightless. • Yet the force of gravity on the shuttle is almost 90 percent as large as at Earth’s surface. • Newton’s laws of motion can explain why the astronauts float as if there were no forces acting on them.
  • 11. Measuring Weight • When you stand on a scale, your weight pushes down on the scale. 3 Newton’s Third Law • This causes the scale pointer to point to your weight.
  • 12. • At the same time, by Newton’s third law the scale pushes up on you with a force equal to your weight. 3 Newton’s Third Law • This fore balances the downward pull of gravity on you.
  • 13. Free Fall and Weightlessness • Now suppose you were standing on a scale in an elevator that is falling. 3 Newton’s Third Law • A falling object is in free fall when the only force acting on the force is gravity. • You and the scale are both in free fall.
  • 14. • Because the only force acting on you is gravity, the scale no longer is pushing up on you. 3 Newton’s Third Law • According to Newton’s third law, you no longer push down on the scale.
  • 15. • So the scale pointer stays at zero and you seem to be weightless. 3 Newton’s Third Law • Weightlessness is the condition that occurs in free fall when the weight of an object seems to be zero.